CADMIUM EXPOSURE INDUCES HISTOLOGICAL DAMAGE, OXIDATIVE STRESS AND IMMUNE RESPONSE IN YELLOW CATFISH

To investigate the effect of different Cd (0 (control), 50, and 200 μg/L Cd²⁺) on Yellow catfish (Pelteobagrus fulvidraco), fish were exposed for 8 weeks before analyzing the histological structure, antioxidant status and immune-related gene expression in gills. The results showed that Cd²⁺ exposure induced significant Cd accumulation and histological changes in gill, such as aneurism, hyperplasia, curling of lamella and cell desquamation. Meanwhile, Cd²⁺ increased the activity of glutathione-S-transferase (GST), glutathione peroxidase (GPx) and anti-hydroxyl radical (AHR) as well as the content of hydrogen peroxide (H₂O₂), and it decreased catalase (CAT) activity and glutathione (GSH) content. However, Cd²⁺ had no significant effect on superoxide dismutase (SOD) activity. In addition, Cd exposure up-regulated tumor necrosis factor-a (tnf-a), major histocompatibility complex (mhc), interleukin-10 (il-10), transforming growth factor-β (tgf-β) and complement factor C3 (c3) expressions, but down-regulated interleukin-1β (il-1β), interleukin-8 (il-8) and lysozyme (lys) transcription levels. These results showed that Cd exposure resulted in the accumulation of Cd, and induced histological damage, oxidative stress and immune response of gill in yellow catfish.